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A software system is presented, capable of integrating various information sources for neurosurgical procedures. These include anatomical data such as a standard 3D DICOM image stacks, atlas data, as well as functional information (e.g. fmri, MEG, EEG). The system is programmed in C++ using Open GL for visualisation, and was developed in a close cooperation with a neurosurgical department to match existing needs. Preoperatively the data may be combined, registered by a rigid or elastic matching process, enriched by user specified planning information such as annotations or trajectories, and visualised in a standard fashion using different segmentation schemes, interactive rotation, zooming etc. Selected portions of the gathered and generated information may then be exported for neuronavigation input in DICOM or a vendor specific format. Intraoperatively, this information may, on the one hand, be simply used as an integrational part of the routinely used navigational data. On the other hand, the system is also capable of interacting with the navigational system to integrate the actual spatial information of the ongoing procedure into the preoperative data, thus allowing further planning and visualisation beyond the scope of the navigational unit. Furthermore, intraoperatively updated information such as intraoperative MR images or electrophysiological data may be integrated and correlated to the existing information. Ongoing developments comprise redistribution of the relevant data for injection onto the screen of the navigational system or into the optical pathway of the (3D capable) microscope display/ocular. This also includes information about the actual automatically optimized accuracy of the navigation process in relation to the head markers in use. [ABSTRACT FROM AUTHOR]

Introduction: Intraoperative guidance using electromagnetic navigation is an upcoming method in maxillofacial surgery. However, due to their unwieldy structures, especially the line-of-sight problem, optical navigation devices are not used for daily orthognathic surgery. Therefore, orthognathic surgery was simulated on study phantom skulls, evaluating the accuracy and handling of a new electromagnetic tracking system., Material and Methods: Le-Fort I osteotomies were performed on 10 plastic skulls. Orthognathic surgical planning was done in the conventional way using plaster models. Accuracy of the gold standard, splint-based model surgery versus an electromagnetic tracking system was evaluated by measuring the actual maxillary deviation using bimaxillary splints and preoperative and postoperative cone beam computer tomography imaging. The distance of five anatomical marker points were compared pre- and postoperatively., Results: The electromagnetic tracking system was significantly more accurate in all measured parameters compared with the gold standard using bimaxillary splints (p < 0.01). The data shows a discrepancy between the model surgical plans and the actual correction of the upper jaw of 0.8 mm. Using the electromagnetic tracking, we could reduce the discrepancy of the maxillary transposition between the planned and actual orthognathic surgery to 0.3 mm on average., Discussion: The data of this preliminary study shows a high level of accuracy in surgical orthognathic performance using electromagnetic navigation, and may offer greater precision than the conventional plaster model surgery with bimaxillary splints., Conclusion: This preliminary work shows great potential for the establishment of an intraoperative electromagnetic navigation system for maxillofacial surgery., (Copyright © 2015 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.)

Background and Purpose: Present methods to extract respiratory myogram interference (RMI) from the Holter-ECG and assess effect of supraventricular arrhythmias (SVAs) onto ECG-based detection of sleep-related breathing disorders (SRBDs) and AHI estimation., Methods: RMI was quantified as residual energy after ECG cancellation or high-pass filtering for different windowing constellations. In 140 cases without (SET&#95;A) and 10 cases with persistent SVAs (SET&#95;B), respiratory polysomnogram annotations served as reference for SRDB detection from Holter-ECGs. We applied our previously published method to identify SRDBs in 1-min epochs and estimate the AHI based on joint modulations in RMI and QRS-area., Results: Sensitivity and specificity of 0.855/0.860 in SET&#95;A dropped to 0.831/0.75 in SET&#95;B. A significantly higher number of wake events in SET&#95;B likely contribute to the asymmetric decrease and is consistent with a tendency to overestimate the AHI., Conclusions: Despite reduced accuracy, RMI and QRS-area appear relatively robust against SVA and promise Holter-based detection at least of medium to severe SRBDs also in patients with SVAs., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Quantitative assessment of myocardial perfusion by myocardial blush grade (MBG) is an angiographic computer-assisted method to assess myocardial tissue-level reperfusion in patients with acute coronary syndromes and microvascular integrity in heart transplant recipients with suspected cardiac allograft vasculopathy. This review describes the ability of quantitative MBG as a simple, fast and cost effective modality for the prompt diagnosis of impaired microvascular integrity during routine cardiac catheterization. Herein, we summarize the existing evidence, its usefulness in the clinical routine, and compare this method to other techniques which can be used for the assessment of myocardial perfusion.

Objective: The aim of this study was to co-record electrical changes using electrocorticography (ECoG) and blood volume changes using intrinsic optical signal (IOS) imaging during the induction, propagation, and termination of cortical spreading depolarizations (CSDs)., Methods: Anesthetized male swine were craniotomized and monitored over 16-20 h. A ten-contact electrode strip was placed on the cortex of one hemisphere for ECoG. An optical imaging recording was implemented using a camera with an optical bandpass filter (564 nm, FWHM:15 nm) and a full spectrum light source. CSDs were induced by mechanical and KCl stimulation. Co-occurrences of ECoG baseline shifts and blood volume changes around electrodes were identified., Results: A mean of 3 CSDs per hour were induced, in a total of 4 swine during 80 h of recording. The propagation of the CSDs increased progressively over the monitoring time. IOS enabled us to clearly visualize the induction, propagation, and termination of CSDs with a spatial resolution within the sub-millimeter range. Every CSD recorded using ECoG could also be observed in IOS imaging, although some blood volume changes of CSDs were observed that terminated before reaching any of the ECoG electrodes., Conclusion: IOS imaging enables an in vivo evaluation of CSD dynamics over a large surface of gyrencephalic brain.

This article aims to identify the potential indicators of obstructive apnea (OA) in the ECG, based on the traces of QRS area from multiple ECG leads. We compare the difference in these traces' phase relation found during and after each OA episode to the difference between the first and second half of the OA and between split halves of epochs of normal respiration (NR).

The aim of this study was to identify precursors of neurocardiogenic syncope (NCS) in ECG parameters of children and adolescents who undergo head-up tilt testing (HUTT). Established linear and non-linear parameters of heart rate variability (HRV) were calculated minute-by-minute in 44 young patients with an NCS history (age 7-20 years, 22 female, 22 male, positive HUTT) and 34 age-matched healthy controls (age 7-20 years, 17 female, 17 male, negative HUTT) during 60 degrees HUTT. The influence of age and gender on the response to tilting was studied using the Wilcoxon rank sum test. We also assessed the predictive power of individual features with respect to HUTT outcome within three temporal windows (0-2 min after tilt; 2-5 min after tilt, and 5-2 min before tilt-back) by means of receiver operating characteristics analysis. Our results indicate that prediction of HUTT outcome should be restricted to subjects in or after puberty. In this group, descriptors based on co-occurrence or joint-recurrence analysis in recurrence plots showed promising predictive power (up to 86% sensitivity and 90% specificity, area under the curve 0.91). Time-domain parameters (standard deviation of differences for successive RR intervals) reached 75% sensitivity and 80% specificity. We conclude that HRV analysis within the first 5 min after tilting provides significant information on HUTT outcome and may be useful in conjunction with more sophisticated classification strategies for shortening HUTT duration in subjects after puberty.

The long QT syndrome (LQTS) belongs to the family of hereditary diseases and can cause life-threatening arrhythmias and leads to sudden cardiac death. Mutations on six genes are responsible for changes in the electrophysiological properties of myocardial cells that are involved in the repolarization phase. In the surface ecg this is expressed by a prolonged QT interval and genotypespecific shapes for the T-Wave. The aim of the study was to find parameters that quantify properties of the repolarization phase which can be used in addition to the established Schwartz score in the process of diagnosing LQTS. Furthermore, ecg features were evaluated for the separation of the LQT subtypes LQT1, LQT2 and LQT3. The combination of the features PtA50 and QTc yielded with 93% sensitivity and 100% specificity the best results in the field of patient identification. Despite the small dataset consisting of 14 patients that was available for the second aim, the achieved results for the morphology indices motivate further research in this field.

We introduce a computer based algorithm for objective quantification of myocardial perfusion to support the diagnosis of cad patients. This new method is based on conventional cine angiographic films. In order to achieve maximal quality of the digital subtraction angiography images, the sequence is synchronized with the ECG. Optionally, the digital images can be motion compensated by a two step matching method. The spatio-temporal spread of blood, or the so-called blush, through the microvasculature to the myocardium--indicated by dye injection--represents a characteristic pattern for the myocardial perfusion. This dynamic temporal pattern is characterized by typical features as the maximal value of blush intensity, of increase and of decrease velocity which correspond with the different phases of flooding in and washout. On the basis of 100 different temporal blush profiles, an algorithm is established which classifies the acquired blush patterns into 4 different grades.

This study examines the utility of recurrence analysis in the field of sleep apnea detection from heart rate series. In 38 patients, ECGs were recorded during sleep in parallel to polysomnography (PSG). Parameters extracted from distance matrices and from recurrence plots (RPs) of the time-delay embedded RR series were tested for their suitability to detect minute-by-minute phases of sleep apnea by means of receiver operating curve (ROC) analysis against the findings of the PSG. Features derived from the continuous distance matrix yielded better results (sensitivity 77%; specificity 78%) than those quantifying the structure of the binary RP (67% and 74%, respectively), accentuating the significance of information on the magnitude of heart rate variations for sleep apnea detection. However, simpler and computationally less demanding spectral techniques yield largely comparable results (77% and 72%, respectively). This raises the question as to whether recurrence analysis of RR series yields additional insight into sleep apnea recognition from heart rate variations.

A software system is presented, capable of integrating various information sources for neurosurgical procedures. These include anatomical data such as a standard 3D DICOM image stacks, atlas data, as well as functional information (e.g. fmri, MEG, EEG). The system is programmed in C++ using Open GL for visualisation, and was developed in a close cooperation with a neurosurgical department to match existing needs. Preoperatively the data may be combined, registered by a rigid or elastic matching process, enriched by user specified planning information such as annotations or trajectories, and visualised in a standard fashion using different segmentation schemes, interactive rotation, zooming etc. Selected portions of the gathered and generated information may then be exported for neuronavigation input in DICOM or a vendor specific format. Intraoperatively, this information may, on the one hand, be simply used as an integrational part of the routinely used navigational data. On the other hand, the system is also capable of interacting with the navigational system to integrate the actual spatial information of the ongoing procedure into the preoperative data, thus allowing further planning and visualisation beyond the scope of the navigational unit. Furthermore, intraoperatively updated information such as intraoperative MR images or electrophysiological data may be integrated and correlated to the existing information. Ongoing developments comprise redistribution of the relevant data for injection onto the screen of the navigational system or into the optical pathway of the (3D capable) microscope display/ocular. This also includes information about the actual automatically optimized accuracy of the navigation process in relation to the head markers in use.

Modelling in systems biology currently lacks clinical applications. As a possible approach leading to clinical relevance the modelling of tissue homeostasis is proposed. As an example a model of epidermal homeostasis is presented which reproduces central morphological and kinetic characteristics of epidermal tissue. Each individual cell is modelled as an agent. The tissue arises as an emergent phenomenon from the interactions of agents. Each agent's behaviour is qualitatively modelled by a simple differentiation state-flow program. Epithelialisation under the influence of parameters concerning stem-cell location is briefly demonstrated.

This study aims at characterizing the short-term time-courses of time- and frequency-domain heart rate variability (HRV) parameters during head-up tilt test (HUTT). Data from 44 young patients with a history of syncope and 34 age-matched controls was analysed in two age-groups related to puberty (< or =13 and > or =14 years), and separately for gender, by extracting minute-by-minute progression of mean RR-interval, standard deviation of RR-intervals (SDNN) and their first difference (SDSD) as well as low-frequency (LF, 0.05-0.15 Hz) energy, high-frequency (HF, 0.15-0.4 Hz) energy and the LF/HF-ratio. Time-courses were individually normalized and averaged after synchronization to the events of tilt and tilt-back/syncope. We observed remarkable age-related differences not only with respect to response to tilting but also regarding the differentiation of patients with positive HUTT from controls with negative HUTT. ROC-analysis in three regions of interest (0-2 min after tilt, 2-5 min after tilt, 5-2 min before tilt-back) revealed generally much weaker and less persistent differences in younger subjects whereas in elders the differences were clearer and often most pronounced immediately before syncope. For both age-groups, the relative change of mean RR provided best separation, however in elders in the ROI just before syncope (sensitivity: 74%, specificity 80%) in young immediately after tilt (sens.: 71%, spec.: 74%). In elder subjects, the relative reduction of SDNN 2-5 minute after tilt achieved almost the same performance (sens.: 74%, spec. 80%) as in the ROI before syncope (sens. 78%, spec. 73%), indicating the existence of rather early precursors of syncope that might help to predict the outcome of the HUTT in subjects in or after puberty.